Non-bullous impetigo is a superficial skin infection commonly seen in children and teenagers. It is caused by Staphylococcus aureus or Group A streptococcus (Streptococcus pyogenes). Constitutional symptoms and fever are minimal. Minor trauma, such as insect bites or abrasions, can predispose to infection. Additional predisposing factors include a warm humid climate, atopic dermatitis, and participation in contact sports.

Although methicillin-resistant S. aureus (MRSA) infection of the skin usually presents as recurrent furunculosis or skin abscesses, MRSA has been shown to cause impetigo. Culture and sensitivities should always be performed in patients with lesions suspicious for cutaneous infection, and empiric coverage for MRSA should be instituted if clinical suspicion is high.